C Program to Calculate Standard Deviation

In this example, you will learn to calculate the standard deviation of 10 numbers using arrays.

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To understand this example, you should have the knowledge of the following C programming topics:

• C Arrays
• Pass arrays to a function in C

This program calculates the standard deviation of an individual series using arrays. Visit this page to learn about Standard Deviation.

To calculate the standard deviation, we have created a function named calculateSD().

Program to Calculate Standard Deviation

#include 
#include 
float calculateSD(float data[]);
int main() {
    int i;
    float data[10];
    printf("Enter 10 elements: ");
    for (i = 0; i < 10; ++i)
        scanf("%f", &data[i]);
    printf("\nStandard Deviation = %.6f", calculateSD(data));
    return 0;
}

float calculateSD(float data[]) {
    float sum = 0.0, mean, SD = 0.0;
    int i;
    for (i = 0; i < 10; ++i) {
        sum += data[i];
    }
    mean = sum / 10;
    for (i = 0; i < 10; ++i)
        SD += pow(data[i] - mean, 2);
    return sqrt(SD / 10);
}

Output

Enter 10 elements: 1
2
3
4
5
6
7
8
9
10

Standard Deviation = 2.872281

Here, the array containing 10 elements is passed to the calculateSD() function. The function calculates the standard deviation using mean and returns it.